gdata.de

ns1.gdata.de, ns2.gdata.de, ns3.gdata.de

Found

Parent zone

de

Delegation from

a.nic.de (194.0.0.53)

NS at the parent

ns1.gdata.de, ns2.gdata.de, ns3.gdata.de

NS in the zone

ns1.gdata.de, ns2.gdata.de, ns3.gdata.de

Checks

• ✓ 3 nameservers #6

  Delegated to ns1.gdata.de, ns2.gdata.de, ns3.gdata.de.
• ✓ Parent and zone agree #7

  The parent delegation and the zone's NS records list the same nameservers.
• !

  Glue differs from the zone

  The addresses at the parent (glue) differ from the addresses in the zone: ns1.gdata.de (glue 92.205.27.67, zone 46.224.32.176). Update the glue at your registrar.

  #8
• ✓ All names resolve #9

  Every nameserver name has an address and is not an alias.
• ✓ Nameservers in different networks #10

  The nameservers are spread over 3 IPv4 /24s and 0 IPv6 /48s.
• i

  All nameservers in one AS

  All nameserver addresses are announced by one network operator (AS24940 (HETZNER-AS - Hetzner Online GmbH, DE): 3 addresses). An outage or attack on that network affects all nameservers; large anycast providers mitigate this, but a secondary DNS provider adds independence.

  #11
• i

  All nameserver names under .de

  All nameserver names are under one TLD, so a problem with that TLD also makes the nameservers unreachable. Some operators use names under two TLDs for extra resilience.

  #12
• !

  No IPv6

  None of the nameservers has an IPv6 address, so IPv6-only resolvers can't reach them.

  #13

3 of 3 addresses answer authoritatively

Found

Checks

• ✓ All respond #14

  All 3 nameserver addresses answered.
• ✓ All authoritative #15

  Every responding nameserver answers authoritatively for the zone.
• ✓ No recursion #16

  The nameservers do not answer recursive queries for other domains.
• !

  Software version disclosed

  These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: ns2.gdata.de: "9.18.39-0ubuntu0.22.04.7-Ubuntu". Hide or replace the version string.

  #17
• ✓ Zone transfers refused #18

  No nameserver allows a zone transfer to the public.
• ✓ TCP supported #19

  All nameservers answer over TCP.
• ✓ EDNS supported #20

  All nameservers support EDNS(0).
• ✓ Public addresses #21

  All nameserver addresses are publicly routable.

serial 2026102001 · primary ns0.gdata.de

Found

Primary (MNAME)

ns0.gdata.de

Contact (RNAME)

postmaster.gdata.de

Serial

2026102001

Refresh / retry

200 s / 200 s

Expire

200 s

Negative TTL

200 s

Serial per nameserver

Checks

• ✓ Serial 2026102001 everywhere #22

  All nameservers serve the same version of the zone.
• !

  Unusual SOA timers

  refresh 3m20s is outside 20m–1d; retry 3m20s should be shorter than refresh 3m20s; expire 3m20s is shorter than 7d; secondaries stop answering too soon when the primary is down; expire 3m20s must be longer than refresh + retry; negative caching TTL (minimum) 3m20s is outside 5m–1d (RFC 2308 recommends 1–3 hours). Current values: refresh 3m20s, retry 3m20s, expire 3m20s, negative TTL 3m20s.

  #23
• i

  Hidden master

  The primary nameserver ns0.gdata.de is not listed as a nameserver: a hidden master that only feeds the public secondaries. That is a common setup; make sure it is not reachable for zone transfers from outside.

  #24
• ✓ Contact postmaster@gdata.de #25

  The SOA RNAME postmaster.gdata.de means postmaster@gdata.de.
• ✓ Date-based serial #26

  The serial 2026102001 follows the YYYYMMDDnn convention (2026-10-20).

Not signed

Found

Validated by resolver

no

Checks

• !

  Not signed

  The zone is not signed with DNSSEC, so answers can be spoofed. Enable DNSSEC at your DNS provider and publish the DS record at your registrar.

  #27